Čekaj ovdje dok ne dođem iz drogerije.

In Croatian, dok + ne is the standard way to say until with a completed event. The ne doesn’t make the clause negative in meaning; it’s part of the “until” construction:

• Čekaj dok ne dođem. = Wait until I come (back). Without ne, dok often means while instead:
• Čekaj dok (ja) dolazim. = Wait while I’m coming (different idea).

After conjunctions like dok, Croatian commonly uses the present tense to refer to a future action, similar to English until I come back (present form, future meaning).
So dok ne dođem is grammatically present, but semantically future.

This is mostly about aspect:

• doći / dođem is perfective (focus on reaching the endpoint: “arrive/come back” as a completed event).
• dolaziti / dolazim is imperfective (focus on the process or repeated coming).

With dok ne ..., Croatian typically prefers a perfective verb because you’re waiting up to a completed point: until I arrive.

Čekaj is the imperative, 2nd person singular (informal you): Wait.
Other common forms:

• Čekajte = imperative 2nd person plural (also used as polite you)
• Čekajmo = Let’s wait

ovdje is an adverb meaning here, so it doesn’t decline and doesn’t take case endings. Cases apply to nouns/pronouns/adjectives, not to adverbs like ovdje, tamo, gdje, etc.

Because iz (out of / from) requires the genitive case.
drogerija is feminine singular, and its genitive singular is drogerije:

• nominative: drogerija
• genitive: drogerije
  So iz drogerije = from (out of) the drugstore.

Usually drogerija is closer to a drugstore/cosmetics & household shop (toiletries, cosmetics, cleaning products, sometimes supplements).
A pharmacy is typically ljekarna in Croatian. So don’t automatically translate drogerija as a place for prescription medicine.

They mean different directions:

• u drogeriju = to the drugstore (motion toward; accusative)
• iz drogerije = from/out of the drugstore (motion away; genitive)

In your sentence, the speaker is returning from there, so iz drogerije fits.

Croatian word order is fairly flexible, but the original is very natural:

• Čekaj ovdje dok ne dođem iz drogerije.

Some alternatives are possible with slightly different emphasis:

• Čekaj ovdje dok iz drogerije ne dođem. (more emphasis on from the drugstore)
• Dok ne dođem iz drogerije, čekaj ovdje. (fronting the time clause for emphasis)

Both are common:

• ovdje = here (often a bit more explicit/precise)
• tu = here/there (nearby) and is very common in speech

So Čekaj tu dok ne dođem iz drogerije. also sounds natural.

Key sounds:

• č (in Čekaj) ≈ English ch in chess, but often a bit “harder”
• đ (in dođem) ≈ a soft j sound, close to j in judge Also note dje in ovdje is pronounced as a cluster (roughly ov-dyeh, depending on accent/dialect).